I just saw the page
http://ringlord.com/publications/jni-howto/.
It has some good detail on using JNI on Linux.
I've added a few clarifying comments in italics below.
Using the JavaTM Native Interface (JNI) is not something many Java programmers have to deal with, but when you do, you need to know something about native applications.
Whether it's Windows, linux, or Solaris,
each native platform and sometimes native compiler or even
the release of the native compiler
has slightly different issues, so I...